1. Field of the Invention
The present invention relates to a technique for printing images on a print medium by ejecting ink drops.
2. Description of the Related Art
Printing apparatus (hereinafter xe2x80x9cink-jet printing apparatusxe2x80x9d) for forming ink dots and printing images on print media by ejecting ink drops are widely used as output devices for computer-created images. The print head of an ink-jet printing apparatus is provided with a plurality of nozzle groups, and these nozzle groups eject mutually different inks in a corresponding manner.
In conventional ink-jet printing apparatus, the color of the ink ejected by each nozzle group is predetermined, and no consideration had been given to the possibility of varying this color in an effective way in order to achieve improved printing performance.
Accordingly, an object of the present invention is to improve printing performance by changing the ink colors ejected by the nozzle groups of a print head.
In order to attain the above and the other objects of the present invention, there is provided a printing apparatus for ejecting ink drops to form dots on a print medium during main scan. The printing apparatus comprises a cartridge mounting section, and a print head, an ink feeder. The cartridge mounting section is capable of mounting an ink tank set storing four basic-color inks of black, cyan, magenta, and yellow, and a supplementary cartridge storing a supplementary solution. The print head has four basic-color nozzle arrays for ejecting the four basic-color inks, respectively, and a supplementary nozzle array for ejecting the supplementary solution. The four basic-color nozzle arrays include a black ink nozzle array for ejecting the black ink. The ink feeder is capable of feeding the four basic-color inks to the four basic-color nozzle arrays, while feeding the supplementary solution from the supplementary cartridge to the supplementary nozzle array. The ink feeder feeds the supplementary solution independently from the basic-color nozzle arrays. The supplementary nozzle array is offset from the black ink nozzle array in a sub-scan direction. The supplementary solution is selectable from a plurality of types of solutions including the black ink.
The printing apparatus will attain high-speed black-and-white printing using the two nozzle arrays (black ink nozzle array and supplementary nozzle array) by selecting black ink for the solution. The quality of photographic images can also be improved by selecting dark yellow ink or gray ink for this solution.
The present invention can be realized in various forms such as a method and apparatus for printing, a method and apparatus for producing print data for a printing unit, a print head, a cartridge, a combination of cartridges, and a computer program product implementing the above scheme.
These and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with the accompanying drawings.